"I lost my sense of individuality, I was just the source of survival for a child. I hadn't imagined how massive the step was from being a couple to adding a baby into the mix."

New research on the happiness of Australians tracks how our satisfaction with life dips and soars during major transitions as we age, using data taken from 27,000 Australians over a period of 12 years, analysed by the Australian Institute of Family Studies.

Sarah is certainly not alone in having her happiness decrease after having a child. In fact the arrival of a child is linked to a drop in life satisfaction which lasts, on average, for six years. The research found:

Leaving home:

Advertisement

This doesn't lead to an overall change in happiness but can arrest a decline in life satisfaction, especially for women.

Partnering:

Moving in with your main squeeze is linked to a marked and sustained increase in life satisfaction for men and women. This is sustained over six years.

Having kids:

There is a rise in life satisfaction before the birth, and a decline after the birth, for both men and women. This decline is only reversed in the sixth year after the birth (which, funnily enough, is when children start school)

Separation from the person you live with:

This is linked with a sharp decline in happiness for both men and women, although this decline began well before separation for women.

Empty nesters:

Contrary to common wisdom ('Mum's overseas blowing my inheritance on a cruise'), there are only modest increases in life satisfaction after the children have all left home.

Retirement:

Life satisfaction for both men and women mostly improves.

Widowhood:

Life satisfaction declines sharply for both men and women before a partner's death, perhaps a reflection of the effect of illness. And happiness hits a low point in the year immediately following a partner's death.

Are Australians a happy lot? Overall, both men and women have a mean life rating of above 7 on a 0-to-10 scale, which shows we are generally satisfied with our lives.

At age 15 we're pretty happy with life, but this sharply declines through our early 20s, then gradually declines until the mid-30s.

Between 30 and the early 50s life satisfaction is relatively stable, (but at its lowest overall level). Then it improves until 80, where it is nearly the highest of the life span, as the graph shows.

Rob and Trish are happy with life at their age. Photo: Joe Armao

Rob, 71, and Trish, 65, have found deep pleasure in hobbies - walking or sports - that keep them active, socialising with friends and their grandchildren.

They were also savvy enough to squirrel away enough money during their working lives that they can continue to travel and enjoy retirement.

Trish lives with early-onset Alzheimers and related health issues, which prompted their recent move into a retirement facility in Wheeler's Hill, in Melbourne's east, where they now have a wide circle of friends.

"When people are in their 60s their children are off their hands, they have a great freedom to do what they like and their responsibilities have diminished," says Rob.

Sarah Appleford went back to work - which she loves - when her son Jack was three months old, because she was worried that if she didn't do something to change her isolation she might slip into post-natal depression.

But life still seemed full of work, childcare and little else. So she and husband Chris, 42, sold their business and most of their possessions, and took Jack on a year-long trip around the world, through South-East Asia, India and Europe.

"To have those experiences all together, to see Jack in different cultures ... we felt re-inspired, re-energised, we had more zest for life," she says.